1. Field of the Invention
The present invention relates to a disk recording/reproducing apparatus having an ascending/descending mechanism for moving a magnetic head used to record and/or reproduce an information signal on a disk recording medium such as a magneto-optical disk, closer to or away from the disk recording medium.
2. Related Background Art
A disk recording/reproducing apparatus which uses a magneto-optical disk as a recording medium enabling an information signal to be recorded using a light beam emitted from an optical pickup apparatus and action of an external magnetic field applied from a magnetic head is conventionally available.
When recording an information signal on a magneto-optical disk, this type of disk recording/reproducing apparatus slides and moves the magnetic head closer to the principal surface of the magneto-optical disk provided with a signal recording area. On the other hand, when reproducing an information signal recorded on the magneto-optical disk, no external magnetic field needs to be applied from the magnetic head, and therefore the magnetic head is moved to a position away from the principal surface of the magneto-optical disk.
Thus, moving the magnetic head away from the magneto-optical disk when the magnetic head need not be used prevents the magnetic head and the magneto-optical disk from mutually sliding over each other and thereby causing the magnetic head and magneto-optical disk to wear out, which improves durability of the magnetic head and magneto-optical disk.
The disk recording/reproducing apparatus which uses as a recording medium a magneto-optical disk for enabling an information signal to be recorded consists of a main body of the apparatus including a disk rotation driving mechanism and an optical pickup apparatus which constitutes recording/reproducing means and a holder supported in a rotatable manner by the main body of the apparatus for loading a disk cartridge in the recording/reproducing position on the main body side. This disk recording/reproducing apparatus is constructed such that a magnetic head is attached to one end of a head support arm which extends over the holder and the head support arm is rotated and operated in accordance with the rotation and operation of the holder.
When recording an information signal, the disk recording/reproducing apparatus including the head support arm for supporting the magnetic head extended on the holder which is supported in a rotatable manner by the main body of the apparatus allows the magnetic head to go into the holder through an opening for insertion of the magnetic head provided in the holder and be loaded (slid over the magneto-optical disk) in the recording/reproducing position. In the case of this disk recording/reproducing apparatus, inserting or removing the disk cartridge while the magnetic head remains in the holder may cause the disk cartridge to collide with the magnetic head, thereby resulting in damage to the magnetic head.
Thus, when inserting or removing the disk cartridge into or from the holder, this type of disk recording/reproducing apparatus moves the magnetic head from the position at which the information signal recorded on the magneto-optical disk is reproduced to an ascent position outside the holder in order to ensure that the disk cartridge is prevented from colliding with the magnetic head.
The disk recording/reproducing apparatus which uses as a recording medium a magneto-optical disk for enabling an information signal to be recorded is structured to control the ascending and descending of the position of the magnetic head according to a recording mode in which an information signal is recorded on the magneto-optical disk and a reproducing mode in which it is possible to eject the magneto-optical disk loaded in the recording/reproducing position and the information signal recorded in the magneto-optical disk is reproduced. This ascending/descending control of the magnetic head is carried out by moving and operating an ascending/descending control lever, which operates the ascending and descending of an ascending/descending operation member to operate the ascending/descending of the magnetic head, using a driving motor. The ascending/descending operation member and the ascending/descending control lever are coupled by a coupling member.
In order to control the ascending and descent positions of the magnetic head according to various operation modes, the disk recording/reproducing apparatus detects the position of the ascending/descending operation lever or coupling member, detects the position of the magnetic head and drives and controls the driving motor according to the detected position of the magnetic head.
A conventional disk recording/reproducing apparatus has three positions of the magnetic head, i.e., recording mode position, reproducing mode position and eject position, and ascends or descends the magnetic head by driving the magnetic head ascending/descending operation member using a cam which is often provided on the coupling member. However, in order to ascend the magnetic head, which is biased by a biasing member or the like at the descent position, against the biasing force, the ascending/descending operation is performed with a limited amount of movement of the ascending/descending operation lever to avoid upsizing of the disk recording/reproducing apparatus, which makes the angle of the cam shaper, requires a driving source (motor) with a large driving force or a deceleration mechanism to obtain the driving force, making it further difficult to reduce the size of the apparatus.